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为了研究柴油车排气管路及消音器结构尺寸等对尾管处尾气温度的影响,进行了排气系统的分段讨论。首先,根据排气温度计算模型——热平衡法模型得出发动机排气歧管处尾气温度的数值计算模型。然后,将尾气在排气管中的流动看作是一维稳态流动,根据能量守恒及一维稳态管对流换热模型,推导出消音器前端尾气温度的数值计算模型。最后,利用相关热力学公式对尾气流经消音器的温度降进行了研究并推导了数值计算模型。以JX493ZLQ3柴油机为研究对象,模拟分析了负荷、转速、环境温度和排气管长度等参数对尾气温度的影响,并通过发动机台架试验验证理论分析了结果的正确性。结果表明:负荷和转速对尾气温度的影响最大,排气管长度次之,环境温度的影响相对最小。
In order to study the influence of diesel exhaust pipe and muffler structure size on tail gas temperature at tail pipe, the exhaust system was discussed in detail. First, a numerical model of the exhaust temperature at the exhaust manifold of the engine is derived from the model of the exhaust temperature calculation-heat balance method. Then, the flow of the exhaust gas in the exhaust pipe is regarded as a one-dimensional steady flow. According to the conservation of energy and the one-dimensional steady-state tube convection heat transfer model, a numerical calculation model of the exhaust gas temperature at the front of the silencer is derived. Finally, the temperature drop of the exhaust flowing through the muffler was studied and the numerical calculation model was deduced by using the relevant thermodynamic formula. Taking JX493ZLQ3 diesel engine as the research object, the influence of the parameters such as load, rotation speed, ambient temperature and exhaust pipe length on the exhaust temperature was simulated and analyzed, and the correctness of the results was verified by engine bench test. The results show that the load and speed have the greatest influence on the tail gas temperature, the exhaust tail length is the second, and the influence of ambient temperature is relatively minimum.